People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

ebola

ebola Stories

Scientists are largely in the dark about how to stop or treat the slew of never-seen-before global health problems of recent years, from the emergence of the deadly MERS virus in Saudi Arabia, to a new killer strain of bird flu in China and an unprecedented Ebola outbreak in West Africa.

The case of Scottish nurse Pauline Cafferkey – the first known Ebola survivor to have an apparently life-threatening relapse – has revived concerns about the health of some 17,000 survivors in Sierra Leone, neighboring Guinea and Liberia.

A growing awareness of how the Ebola virus can hide in parts of the body such as eyes, breasts and testicles long after leaving the bloodstream raises questions about whether the disease can ever be beaten.

The three West African countries at the heart of an Ebola epidemic recorded their first week with no new cases since the U.N. World Health Organisation recognized the outbreak in March 2014, it said on Wednesday.